In a screw-top jar, combine the soy sauce, sesame oil, ginger, vinegar, vegetable oil, mustard, and garlic and shake well. In a large saucepan, bring the water to a boil. Stir in the rice, cover, remove from the heat, and set aside 5 minutes or until all the liquid is absorbed. Allow the rice to cool In a large bowl, combinethe cooled rice, peas, onions, chicken, celery, and bell peppers and toss. Pour the dressing over the rice mixture and toss. Transfer to a serving dish. Cover and chill before serving.